The present invention relates to a sputtering target-backing plate assembly that is used when magnesium (Mg) is the sputtering target material, and particularly relates to a sputtering target-backing plate assembly in which the bonding strength between the target and the backing plate has been increased in order to improve the sputtering efficiency, as well as to a method of producing the same.
In recent years, a magnesium (Mg) sputtering target is required for use in MRAM. A target is usually bonded to a backing plate and subject to high-power sputtering in order to improve the production efficiency, but the problems resulting from such high-power sputtering are the strength and cooling power of the backing plate itself, and the bonding strength between the backing plate and the target.
As a conventional technology, some ingenuities have been proposed for improving the bonding strength between the target and the backing plate. To introduce these proposals, for instance, there is a technology in which Ag or Ag alloy is used as the insert material upon bonding a target material of Al or Al alloy to a backing plate, these materials are loaded, and subsequently solid-phase diffusion is performed thereto (refer to Patent Document 1).
Moreover, there is a technology in that convexoconcave is concentrically formed on the bonding surface of the sputtering target and the backing plate, and they are bonded via HIP, hot press, or solid-phase diffusion bonding in an interdigitated state (refer to Patent Document 2).
Moreover, there is a technology of performing solid-phase diffusion bonding via an insert material having a lower melting point than the target when bonding a target material having a melting point of 1000° C. or higher to a backing plate (refer to Patent Document 3).
Moreover, there is a method of interposing fine copper powder between the sputtering target and the backing plate, and bonding them at a low temperature (refer to Patent Document 4).
Moreover, there is a technology of bonding the sputtering target to the backing plate, via an Al or Al-alloy spacer, based on explosion bonding or hot rolling (refer to Patent Document 5). Moreover, there is a sputtering device in which the surface area is increased by providing convexoconcave to the cooling surface of the backing plate (refer to Patent Document 6).
In these Patent Documents, the bonding method has been devised in order to increase the bonding strength between the sputtering target and the backing plate, but there is hardly any reference to the bonding strength resulting from the materials that are used as the backing plate and the target. In particular, there is no disclosure whatsoever regarding problems in the case of preparing a target from magnesium, and the means for solving such problems.